Within current mobile communications networks, the so-called Cell Broadcast is designed for simultaneous delivery of messages to multiple users in a specified area. Cell Broadcast allows transmitting data (e.g. any text or binary message) to all idle mobile terminals connected to one or a set of cells. Cell broadcast messages are usually send periodically with a certain repetition period.
As described e.g. in 3GPP TR 25.925, v 3.5.0, titled “Radio Interface for Broadcast/Multicast Services”, 2004, Chapter 6.3.6.4, Cell Broadcast Service/Multicast Service data is received on a broadcast/multicast channel, which has to be available to all users (mobile terminals) in a given cell range. The signal quality (e.g. signal-to-noise ratio SNR) decreases over the distance (schematically shown in FIG. 1) between sender (e.g. a base station) and receiver (e.g. a mobile device also being referred to as user equipment UE, mobile terminal or mobile (phone)). As all the users of said services shall receive the signal irrespective of their current location within the cell range, no power control mechanisms are in place; the signal is transmitted at maximum power (e.g. at a power such that the remotest user will receive the signal with sufficient quality, e.g. signal-to-noise ratio. Thus, users located closer to the base station receive a much stronger signal than the users located at the border of the cell. This means that most of the users will receive signals having higher quality than needed.
Mobile terminals are especially designed to consume as little as possible power in idle mode, (i.e. in a mode, wherein most of the components—including the receiver—are generally disabled, and only to be enabled periodically for short time periods in order to receive information from the network, check the signal power, etc.) However, when e.g. Cell Broadcast Service—CBS—is activated, the stand-by time of the corresponding mobile devices (or user equipments UE) decreases, as (in addition to the discontinuous reception—DRX—cycle) a multiple of CBS occasions need to be received. One solution to avoid such power consumption is to switch-off the CBS service; this however means to (at least temporarily) disconnect from valuable services. Further it is to be noted that CBS might be mandatory in some countries.
With regards to these facts, there might be a high demand to optimizing the reception scheme of broadcasted/multicasted signals (i.e. signals to be received by a plurality of receivers).